Nik Software has been making some excellent high-end software for a long time now. If you're a serious photography enthusiast then you may have heard of or even already use Efex Pro - a black and white conversion tool that's been received with critical acclaim.

But now you needn't be a serious photographer at all, because the company's Snapseed retouching software, available for iPhone and iPad, has bags of features on offer. And best of all it's totally free.

Snapseed

There's hardly a shortage of photography apps for the iPhone. In fact there are already shed loads in the App Store. Some, such as Instagram or Photoshop Express, are free - so is there room for another app in a crowded market place?

In short, yes, we reckon so. Nik Software isn't mucking about with this app - which, by the way, used to cost £2.99 for iPad - as Snapseed is an easy to use, responsive and delivers great results.

Open up the app and there's a row of adjustment tools at the bottom or left-hand side, depending on portrait and landscape orientation of your device. Tools are extensive too, so take a deep breath: there are automatic, selective adjust, tune image, straighten, crop, details, black & white, vintage, drama, grunge, centre focus, frames, and tilt-shift that pretty much every base.

In the centre of the screen, or to the right-hand side if you're working in a landscape orientation, is space for the image you're working in.

Whether sourcing a shot from your device's library, importing a picture taken on a dedicated camera or snapping a new shot using an iPhone's camera there are few limitations to what can be imported. If you have an iPad 3, for example, then Nik Software says that the maximum image size is up to a massive 20.25-megapixels and that the software will read JPEG, TIFF and Raw files (via a camera connector).

Processing is pretty quick too, shown by a percentage counter to the top of the image, though things slow down a little as image size increases. The 13MB, 24-megapixel Nikon D3200 image sample that we loaded into the software took some 10 seconds to process into black and white on an iPhone 4 - that's not bad considering the size and scale. However the file was then downscaled to 16.7-megapixels - hardly small, but shows that there are limitations to different devices capabilities.

Once a tool is selected there are three main controls to make adjustments: swipe up or down to select between the various sub options, such as filter strength and saturation in the drama adjustment; press the screen and apply the adjustment by moving left and right through +/-100; and a pinching motion will, where relevant, adjust circular selection or, for example, the tilt-shift blur area.

Although it's not possible to see images at a 100 per cent pixel level, the sharpening and structure tools found within the detail adjustment are the exception. Here it's possible to click and drag a magnifier over any part of the image to see how subtle (or harsh) your adjustment is.

Black and white adjustment is, in true Nik style, excellent too. As well as brightness, contrast and grain filters there are colour filters to produce different b&w results.

Once you're done adjusting, or stacking on all manner of adjustments, you can re-save the file, email it, open it in another app such as Dropbox, or post it to Flickr, Facebook, Twitter or Instagram with the click of a button.

So whether you want to make some serious adjustments, or just have a good ol' muck around with some "fun" filters, Snapseed has the versatility to cater for both. And cater for both well.

Given that many basic apps charge 69p for a simple tilt-shift effect - something that's also in Snapseed amid all its other goodies - you'd be mad to miss this free app. Yup, Snapseed is seriously good stuff.